This invention relates to a dispenser for liquid material, such as shoe polish, comprising a container and an applicator by means of which a small quantity of the material can be removed from the container by dipping and applied to the surface to be treated with the material.
Although the invention can be applied in many fields, for instance in the field of cosmetics, it will be described herein with particular reference to its application as a shoe polish dispenser.
A drawback of shoe polish dispensers of the above described type is that when the applicator is being removed from the container for a first application of the material or after dipping it into the opened container, an uncontrollable amount of liquid material can adhere to the applicator allowing for the spillage excess liquid, which is naturally undesirable. An associated problem is that when a material-absorbing end of an applicator is dipped into a mass of liquid material, it is difficult to absorb a controlled small amount of the material, for instance a small amount of shoe polish for spreading it on a shoe surface. A further problem is that after some time the applicator will dry out owing to evaporation.
Applicant's earlier European patent application No. 90200168.4 discloses a dispenser for liquid material, comprising a container and an applicator by means of which a small quantity of the material can be removed from the container by dipping and then applied to a desired surface. In one embodiment, the dispenser comprises a tube extending from the mouth of the container into the vicinity of the bottom thereof, at least the lower end of this tube forming a proper fit for an applicator inserted into the tube. This tube communicates only at the lower end thereof with the otherwise closed, annular container space around the tube, so that in accordance with the principle of the Torricellian tube, always only such an amount of liquid material is supplied from the closed annular space through the passage adjacent the bottom to the inner space of the tube, that a hydrostatic equilibrium is reached with a low liquid level in the inner space of the tube and a much higher level in the closed annular space where a subatmospheric pressure prevails above the liquid. Each time an amount of liquid has been removed from the tube by the applicator such that air can flow into the annular space, the tube is replenished from the annular space up to the original, low level. This means that by inserting the applicator into the tube to a given depth, defined for instance by a stop, the material-absorbing end of the applicator is always dipped into the liquid to the same depth and therefore the same amount of material is withdrawn from the stock.
With that dispenser the objects contemplated are indeed accomplished, namely that each time the material-absorbing end of the applicator is dipped into the mass of liquid material, only a small amount of the material is absorbed, so that spillage, evaporation of the liquid and drying out of the typically spongy applicator are avoided.
However, the above described dispenser works optimally only if the viscosity of the product is exactly matched with the dimensions of the dispenser parts.
The object of the present invention is to provide a dispenser of the type described, the operation of which is not based on the Torricellian principle and which, as a consequence, is more universally applicable, while spillage is avoided in a constructively simple manner, a reasonable control is obtained of the amount of liquid to be absorbed when dipping the applicator, and evaporation of the liquid and drying out of the applicator are avoided.